Various enveloping principles are known from conventional technology. U.S. Pat. No. 7,475,522 B2 shows a filling station with direct feeding of the envelopes from above. Coming from the envelope leader, an envelope moves against a stop, is received by two worm wheels, is separated and is vertically inserted into the filling plane. Once the envelope has been opened and filled, the stop is opened and the envelope is transported out of the filling station. EP 1 275 523 A describes an approach to inserting a material into an envelope, the envelopes being fed from above, separated by worm wheels and fed to the filling station by means of the movement of the worm wheels. EP 1 473 173 A describes an enveloping machine wherein the envelopes are fed to the filling station from below. Feeding is performed by means of worm wheels, which are enabled for envelope output subsequent envelope filling.
The above-described filling stations for enveloping machines have short travel paths in the feeding of the envelopes to the filling station. In order to transport a subsequent envelope into the filling station, it is useful to bridge a movement path, which essentially corresponds to the thickness of the envelope and/or to the spacing of a screw channel. While the filled envelope is removed, the next envelope is already available for envelope opening. Avoidance of long travel paths and of the long dead times resulting therefrom enables that feeding of the envelopes to the filling need not be performed at high speeds; rather, low speeds may be used. Therefore, said approaches are suitable for large cycle outputs. U.S. Pat. No. 7,475,522 B2 relates to an embodiment of a filling station wherein the cycle output may amount to 30,000 envelopes/h. The short travel paths and the low speeds also enable compact design of the system.
However, the above-described known approaches or solutions are disadvantageous in that two of the three known solutions, namely the approaches described in U.S. Pat. No. 7,475,522 B2 and in EP 1 275 523 B1, disclose feeding of the envelopes from above. This is disadvantageous since in case of feeding being performed from above, a subsequent envelope can get caught in the window of the preceding envelope.
In addition, the three above-described approaches, wherein envelope filling is performed into an envelope with the flap located at the top and the throat opening located at the bottom, involve increased effort for preventing a collision of the material being introduced at the throat opening, and thereby significantly restrict format and shape flexibility. In addition, all of the above-described solutions provide a approaches without any lateral guide and/or without the envelope being spread open in the filling process, which considerably reduces process reliability and lowers the filling limit. Moreover, design and operation are expensive due to the worm wheels used.
According to the three solutions described above, opening the envelope as well as keeping it open are performed exclusively by means of blow air. However, this is reliable to a limited extent only, since, on the one hand, already minor adhesions on the inside of the envelope make it significantly more difficult to open the envelope by means of blow air only, and, on the other hand, keeping the envelope open by means of blow air only may result in that the filling material is partly or even completely “blown out” of the envelope.